The model VBS-100 actuator steps in 36° increments for opening and closing the choke. This is accomplished by a pawl and drive spool arrangement that directly drives the choke stem coupling. The pawl is extended to contact and rotate the drive spool member. This provides a constant loading force to produce the required torque output.
The pawl and piston are designed for positive spring return to ensure that each cycle stroke is consistent. The pawl is always disengaged to allow for reverse or manual operation at any time. Manual operation is easily obtained via the hex shaft on top of the actuator. Rotation of this shaft will directly drive the choke stem opened or closed.
The VBS-100 stepping actuator is equipped standard with a 5-kΩ potentiometer and a 4- to 20-mA transmitter for remote feedback of choke position. An optional limit switch module is available to directly sense the 4- to 20-mA signal to control the open and closed solenoids. This module can be adjusted to any setpoint within the choke stem travel. Solenoid valves can be supplied and installed at the factory.
- Pneumatic supply at 80 to 120 psi maximum
- Hydraulic supply at 1,500 to 3,000 psi maximum
- Visual position indicator
- Manual override via hex shaft
- Fail-safe last position
- Watertight housing with corrosion-resistant coating
- Wiring junction box
- Field tested